Doesn't look like anything BSA imported into the US in the '60s or '70s. Certainly not 1970. The front fender looks like it fits this bike but looks like one from a Clymer Indian Enfield, as does the shape of the handlebars.
Mid-1950s to early 1960s vintage... It is a Puch 250 2-stroke "twingle"; a split twin....common main connecting rod with rear cylinder controlling intake ports and front cylinder controlling exhaust.
Sold in the US as an "Allstate". Split fuel tank had oil in left side tank compartment w/oil pump delivery system.
Handlebars and exhaust do not seem to be correct. There was an Enduro model with high pipes but different mufflers ( and a different frame)